code: def __len__(self):
      return self.len
  
file_path: pytorch-lightning/examples/pytorch/bug_report/bug_report_model.py
imports: import os
  import torch
  from lightning.pytorch import LightningModule, Trainer
  from torch.utils.data import DataLoader, Dataset
label_desc: Use image node_id 3 for calling the RandomDataset obj's underlying member method code with example usage: obj.__len__() and returns: self